Abstract

The surface conditions favoring a negative electron affinity (NEA) on hexagonal boron nitride grown by radio-frequency plasma-assisted chemical vapor deposition(CVD) have been investigated by ultraviolet photoelectron spectroscopy. The NEA condition on the film appears to be resistant to oxygen-plasma or in-vacuo atomic oxygen treatment. It is not certain whether the segregation of bulk hydrogen onto the surface helps to promote the NEA; the depth profile of the depositedfilm reveals about 0.01%–0.1% atomic concentration of hydrogen. High temperature annealing at results in a positive electron affinitysurface (PEA). Reexposure of PEA surface to atomic hydrogen at room temperature regenerates the NEA condition. This is evident of the role of superficial hydrogen in promoting NEA on the film.